Introduction: This research aimed to investigate the impact of mentors' resources on the premature termination of mentoring relationships in challenging contexts as well as mediating psychological processes.

Method: In two studies, we analyzed the data of 98 mentors from an online mentoring program for girls in STEM subjects and the data of 60 mentors from a school-based mentoring program with talented youth. Participants were surveyed with a standardized questionnaire about their mentoring experiences during the first peak of the COVID-19 pandemic in Germany, which created a challenging context.

Results: The results indicated that a reduction of mentoring resources is associated with an increased risk of premature match closure. This effect of resources was mediated in two ways: by (a) mentors' confidence in their mentoring abilities, which predicted feelings of helplessness, and (b) mentors' beliefs in the modifiability of deficits and the stability of abilities, which predicted adaptive responses to failure. Furthermore, mentors in the school-based program reported a more significant reduction in mentoring resources, which, in turn, was more strongly associated with premature match closure than in the online mentoring program.

Discussion: This suggests that online mentoring might be more robust than face-to-face mentoring under unfavorable environmental conditions. Overall, our study points to equipping mentors with adequate resources and offering ongoing support, especially in challenging environments.